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    <title>Document</title>
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    <script>
        async function main() {
            // 1. 如果返回值是一个非promise类型的数据
            // return 1
            // 2. 如果返回的是一个promise对象
            let p = new Promise((resolve, reject) => {
                // resolve('ok')
                reject('err')
            })
            try {
                let res = await p
                console.log(res)
            } catch (e) {
                console.log(e)
            }
            return p
            // 3. 抛出异常
            // throw new Error('err')
        }
        let result = main()
        console.log(result)
    </script>
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